Wireline grease injection apparatus having removable grease injection tubes

ABSTRACT

Replaceable grease injection tubes permit removal and replacement of such tubes without requiring wireline and associated tools to be removed from a well, or wireline tools to be removed from wireline and thereafter spliced or re-threaded on such wireline. Replaceable grease injection tubes include opposing semi-cylindrical members that can be joined together to form a central bore for receiving wireline and facilitating a pressure seal using injected grease or other fluid having desired pressure sealing characteristics.

CROSS REFERENCES TO RELATED APPLICATION

NONE.

STATEMENTS AS TO THE RIGHTS TO THE INVENTION MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

NONE

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention pertains to a grease injection system for performing wireline operations in oil and gas wells. More particularly, the present invention pertains to a wireline grease injection apparatus having a grease injection tube that can be quickly and efficiently removed and/or replaced with wireline in a well. More particularly still, the present invention pertains to a wireline grease injection tube that can be removed and/or replaced without requiring complete removal of wireline or associated tools from a well, or cutting of such tools from the wireline.

2. Brief Description of the Prior Art

During the drilling of oil and gas wells, a hole is typically bored into the earth's crust using a rotating bit attached to the distal end of a tubular work string. As a well advances deeper into the earth's crust, it typically encounters porous and permeable rock formations containing pressurized fluids, such as gas, oil and/or water. Such “formation” pressure generally increases with depth.

In most cases, the primary mechanism for controlling such downhole formation pressure is hydrostatic pressure imparted on the exposed formation(s) in the well by a column of fluid, typically drilling mud, contained within the well bore. Ideally, this hydrostatic pressure should be roughly equivalent to the pore pressure of said formation(s), resulting in a balanced system and little or no pressure observed at the earth's surface. However, in the event that such hydrostatic pressure is insufficient, the pressurized gas and liquids contained within said down hole formation(s) can overcome such hydrostatic pressure, invade the well bore and displace drilling fluid contained therein. Under such a scenario, prompt corrective action is required, or else control of the well can be lost and a blowout can occur.

After a well has been drilled to a desired depth, large diameter pipe called casing is typically installed in the well and cemented in place. Such casing provides structural integrity to a well bore, isolates down hole formations from one another, and prevents pressurized formation fluids from entering the well bore. In most cases, a string of production tubing is concentrically inserted inside the casing, and an assembly of valves, commonly referred to as a “Christmas tree,” is installed at the earth's surface on the upper end of the casing. The casing can be perforated—typically using high-energy jet charges—to allow communication between a pressurized oil or gas bearing formation (on the outside of the casing) and the inner bore of the casing. After being fully equipped and completed, a well is typically ready to commence producing.

At different times during the life of a well, whether a well is in the process of being drilled, or is already producing, various types of wireline tools can be used to perform different functions within such well. In virtually all cases, such wireline tools are lowered into the well from the surface, and suspended/manipulated within the well using a flexible wireline or cable. Typically, a sufficient length of wireline is maintained on a spool or drum at the surface. The leading end of the wireline is unspooled, and vertically aligned over a well and suspended in place using an arrangement of beneficially positioned sheaves or pulleys.

A wireline lubricator is typically used at the surface when performing various wireline services in cased or open hole well operations. The lubricator assembly, which is usually attached to the top of a Christmas tree (in the case of a producing well) or blowout preventer assembly (in the case of a well that is being drilled), typically comprises a tubular housing having an inner chamber of sufficient diameter and length to completely contain the wireline tool(s) being used. If it becomes necessary to repair or otherwise perform maintenance on the wireline tools while wireline operations are being performed, the wireline tools can be raised out of the well and into the lubricator. Once the wireline tools are safely inside the lubricator, the master valve of the Christmas tree (in the case of a producing well), or the rams of the blowout preventers (in the case of a well that is being drilled), can be closed to seal off or isolate such pressure from the lubricator. With the well pressure safely contained below the Christmas tree or blowout preventer assembly, as the case may be, the lubricator can then be safely removed from the well and the wireline tools can be accessed.

When a Christmas tree or blowout preventer assembly is open, wellbore pressure is typically communicated to the inner chamber of the lubricator. As such, a grease injection assembly is typically provided at or near the top of a wireline lubricator assembly in order to control pressure observed in a well when wireline tool(s) are being raised or lowered in such well. In most cases, a grease injection assembly comprises an outer housing having a fluid inlet port and a fluid outlet port. The grease injection assembly further comprises at least one grease tube disposed within said outer housing. Each such grease tube has a central bore that extends along the length of such tube. Frequently, multiple grease tubes are used in such grease injection assembly. Such grease tube(s) are vertically oriented within the outer housing, with the central bores of such tubes aligned with one another.

In operation, the leading end of the wireline is threaded through the aligned central bores of such grease tube(s). The internal diameters of such central bores are beneficially sized so that a very small gap exists between the external surface of the wireline and the internal surfaces of the central bore(s) of the aligned grease tube(s). When the grease injection assembly is being used, grease or other viscous fluid having desired characteristics is then introduced into such gap (that is, the annular space between the outer surface of the wireline and the inner diameter of the grease tube) under pressure. Such grease or other viscous fluid fills the gap between the outer surface of the wireline and the inner surfaces of the aligned grease tubes, and forms a dynamic pressure seal. This pressure seal prevents pressurized well bore fluids from invading the annular space between the wireline and the aligned grease tube(s) and escaping out of the top of the lubricator, while permitting wireline tools to be raised and/or lowered within the well.

After the wireline has been threaded through the aligned bore(s) of such tube(s), the desired wireline tools are then connected to the leading end of the wireline. Thereafter, such tools can be retracted into the lubricator, and the lubricator can be mounted to the top of a Christmas tree or blowout preventer assembly. Thereafter, the valves of said Christmas tree, or the rams of said blowout preventer assembly, can be opened and the wireline tools can be lowered into the well bore via the wireline. The dynamic pressure seal provided by the grease injection assembly prevents pressurized well fluids from escaping through the top of the lubricator.

Over time, wireline can become worn or deformed due to a variety of factors including, but not necessarily limited to, excessive use, and/or prolonged exposure to elevated downhole temperature and pressure. In some cases, the cross-sectional shape of the wireline, which is normally circular, can instead become oval-shaped. In other cases, the cross-sectional diameter of the wireline can be reduced. Similarly, the central bores of grease tubes can likewise become misshapen or deformed due to various factors such as excessive use, elevated pressure and the like. When the wireline, grease tubes, or both, become deformed, grease injected into the annular space between the wireline and grease tubes may not adequately fill such irregular gap and establish a uniform pressure seal.

When grease tubes become worn or deformed, it is frequently necessary to remove such grease tubes and replace them with new or unworn grease tubes that will permit establishment of a uniform pressure seal. When wireline becomes deformed, it is frequently impossible to replace the wireline (which typically entails replacement of an entire spool of wireline) in the field. Under such a scenario, it is often necessary to remove the existing grease tubes and replace them with tubes having smaller central bores that permit establishment of a uniform pressure seal.

When replacing conventional grease tubes during wireline operations, the wireline and associated tools must first be retrieved out of the well and positioned within the wireline lubricator. When the wireline and tools have been removed from the well, and the wireline tools are positioned safely within the wireline lubricator, the valves of the Christmas tree (or, the rams of the blowout preventer assembly, in the case of a well that is being drilled) can be closed. Thereafter, the lubricator can be removed from the Christmas tree or blowout preventer assembly, and the tools can be removed from the wireline (typically, by severing such wireline). With the tools removed from the wireline, the existing grease tubes can be removed, and new grease tubes can be threaded on the end of said wireline. The tools can then be spliced on the end of the wireline and loaded back into the wireline lubricator. The lubricator can then be mounted to the top of the Christmas tree or blowout preventer assembly, and the valves on such Christmas tree or the rams of the blowout preventer assembly can be opened, thereby permitting access into the well bore. Thereafter, the wireline tools can be lowered into the well and wireline operations can resume.

As set forth above, the process of replacing wireline grease tubes can be an involved and time-consuming process. Because drilling rigs and associated goods and services are typically rented on a daily or hourly basis, the time delay associated with replacing such grease tubes can be extremely expensive. Further, as discussed above, the current method of replacing grease tubes requires the cutting of wireline and splicing of tools on the severed wireline. Such actions can result in reduced or diminished wireline strength and performance by such wireline tools.

Accordingly, it is desirable to have a grease injection apparatus having replaceable grease tubes that can be easily and quickly removed and replaced while wireline is disposed in a well. Such grease tubes should be capable of being removed with a minimum of downtime, and without the need for removal of such wireline tools and re-splicing of such tools on said wireline.

SUMMARY OF THE PRESENT INVENTION

The present invention comprises a grease injection assembly that can be connected to the top of a wireline lubricator assembly and serves to provide a pressure seal to control pressure observed within a well while wireline operations are being conducted in such well. Said grease injection assembly generally comprises a grease injection body member having an inner chamber, as well as an inlet assembly and an outlet assembly. A supply line provides a conduit to provide grease or other flowable substance having desired characteristics to said grease injection body member via said inlet assembly. A recovery line similarly provides a conduit to recover excess grease (or other similar substance having desired characteristics) from said grease injection body member via said outlet assembly. A pack-off assembly is beneficially connected to the upper end of the grease injection assembly to prevent grease or other flowable substance pumped into said grease injection assembly from exiting the top of said assembly.

At least one grease injection tube (not depicted in FIG. 1) is installed within said grease injection chamber. Each such grease injection tube has a substantially cylindrical configuration and a central bore that extends along the length of such tube. Depending on well conditions and other factors, multiple grease injection tubes may be installed end-to-end, with their respective central bores aligned, within said grease injection chamber.

The grease injection tube of the present invention generally comprises opposing elongate semi-cylindrical members that can be joined together to form a complete tube. When assembled, the grease injection tube of the present invention has a similar shape and substantially identical dimensions as prior art grease injection tubes widely known in the art.

Unlike conventional grease injection tubes, the grease injection tubes of the present invention permit removal and replacement of said tubes while wireline is suspended in a well, and without requiring such wireline or any accompanying wireline tools to be completely removed from a well. Further, such grease injection tubes of the present invention permit removal/replacement of such tubes without the need for severing tools from wireline or splicing tools onto such wireline.

When removal or replacement of the wireline tubes of the present invention becomes necessary or desirable—including during times that wireline and any associated wireline tools are in a well—wireline blowout preventers can be closed around the wireline at the surface. In this manner, the wireline (and any associated tools) remain in the well, with any well pressure safely isolated below such blowout preventers. Thereafter, any trapped pressure can be released from the grease injection assembly of the present invention, and the grease injection assembly can be opened to expose the grease tubes of the present invention. Once exposed, the grease injection tubes of the present invention can then be removed and replaced with new tubes. Thereafter, the grease injection assembly of the present invention can be reinstalled, and wireline operations can be safely resumed.

Means are provided for securing said members to each other. In one embodiment of the present invention, fastening means are provided for securing said members together.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, the drawings show certain preferred embodiments. It is understood, however, that the invention is not limited to the specific methods and devices disclosed.

FIG. 1 depicts a side cut-way view of prior art wireline operations conducted in a well using conventional grease injection equipment.

FIG. 2 depicts a side perspective view of a prior art grease injection tube.

FIG. 3 depicts a sectional view of a prior art grease injection tube taken along line 3-3 of FIG. 2.

FIG. 4 depicts a sectional view of a prior art grease injection tube taken along line 4-4 of FIG. 3.

FIG. 5 depicts a side perspective view of one embodiment of the grease injection tube of the present invention.

FIG. 6 depicts a sectional view of a grease injection tube of the present invention taken along line 6-6 of FIG. 5.

FIG. 7 depicts a sectional view of a grease injection tube taken of the present invention along line 7-7 of FIG. 5.

FIG. 8A depicts an exploded perspective view of the grease injection tube of the present invention.

FIG. 8B depicts an alternative exploded perspective view of the grease injection tube depicted in FIG. 8A.

FIG. 9 depicts a side perspective view of a first alternative embodiment of the grease injection tube of the present invention.

FIG. 10 depicts a sectional view of grease injection tube taken along line 10-10 of FIG. 9.

FIG. 11A depicts an exploded perspective view of a portion of the first alternative embodiment of the grease injection tube depicted in FIG. 9.

FIG. 11B depicts an exploded perspective view of a portion of the first alternative embodiment of the grease injection tube depicted in FIG. 9.

FIG. 12 depicts a side perspective view of a second alternative embodiment of the grease injection tube of the present invention.

FIG. 13 depicts a sectional view of the second alternative embodiment of the grease injection tube of the present invention taken along line 12-12 of FIG. 13.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION

Referring to the drawings, FIG. 1 depicts a side cut-way view of wireline operations being conducted in well 10 using a conventional prior art grease injection assembly 30. Well 10 extends into the earth's crust 11. Christmas tree 12, which typically comprises at least valve assembly 12 a and 12 b, is disposed at the upper extent of well 10. Lubricator assembly 20 is mounted to the top of a Christmas tree 12 in a manner well known to those skilled in the art. It is to be observed that certain wells may not be equipped with a Christmas tree. For example, wells that are being drilled may not be equipped with a Christmas tree. In such cases, lubricator assembly 20 may instead be connected to a blowout preventer assembly (not shown in FIG. 1) having a configuration well known to those having skill in the art of well drilling.

Lubricator assembly 20 comprises wireline blowout preventers 21 and tubular body section 22. Grease injection assembly 30 is connected to the top of lubricator assembly 20 and serves to provide a pressure seal to control pressure observed within well 10 while wireline tool(s) 50 are being utilized in such well. Grease injection assembly 30 generally comprises grease injection housing 31 having an inner chamber, as well as an upper inlet assembly 32 and lower outlet assembly 33. Grease supply line 34 provides a conduit to deliver grease or other flowable substance having desired characteristics to grease injection housing 31 via upper inlet assembly 32. Grease recovery line 35 similarly provides a conduit to recover excess grease (or other similar substance having desired characteristics) from grease injection housing 31 via outlet assembly 33. Pack-off assembly 40 is connected to the upper end of grease injection assembly 30 to prevent grease or other flowable substance pumped into grease injection assembly 30 from exiting the top of said assembly.

Grease injection assembly 30 includes at least one grease injection tube (not depicted in FIG. 1) installed within the chamber of grease injection housing 31. Each such grease injection tube has a substantially cylindrical configuration and a central bore that extends along the length of such tube. As discussed above, multiple grease injection tubes are frequently installed end-to-end, with their respective central bores aligned, within the chamber of grease injection housing 31.

During conventional wireline operations, wireline tools 50 can be manipulated within well 10 via flexible wireline 51. Although not depicted in FIG. 1, a sufficient length of such wireline 51 is typically wound on a spool situated in the general vicinity of well 10. The leading end of the wire is typically unspooled, vertically aligned over well 10, and suspended using an arrangement of beneficially positioned sheaves or pulleys. Such wireline tools can be used to perform any number of beneficial functions within well 10. By way of illustration, but not limitation, such tools 50 can be used to perform beneficial work within well 10 and/or evaluate subsurface formations encountered by well 10. Although wireline 51 may comprise “electric line” that can be used to conduct electrical charges to tools 50, it is to be observed that such wireline 51 can also comprise non-conductive “braided line” or “slick line.” As depicted in FIG. 1, wireline 51 is concentrically disposed through pack-off assembly 40, grease injection assembly 30, wireline lubricator assembly 20 and the central bore of Christmas tree 12.

Tubular body section 22 of lubricator assembly 20 is of sufficient size and length to totally contain wireline tool(s) 50. If excessive, unexpected or otherwise undesirable well pressure is encountered in well 10 while wireline operations are being performed, wireline tools 50 can be raised out of such well and into said tubular body section 22 of lubricator assembly 20. Once such wireline tools 50 are safely retracted inside tubular body section 22 of lubricator assembly 20, master valve 12 a of Christmas tree 12 can be closed to isolate such well pressure from lubricator assembly 20. Wireline tools 50 can then be safely removed from the lubricator assembly 20, with the well pressure being contained below master valve 12 a of Christmas tree 12.

FIG. 2 depicts a side perspective view of a prior art grease injection tube 60. Although the precise configurations and dimensions of existing grease tubes may vary, prior art grease injection tube 60 comprises substantially cylindrical central body section 61. Upper end section 62 is disposed at the upper end of central body section 61 and has an outer diameter less than that of said central body section 61. Upper end section 62 also has tapered outer shoulder 64 and tapered inner shoulder 65. Lower end section 63 is disposed at the lower end of central body section 61 and also has an outer diameter less than that of said central body section 61. Lower end section 63 also has tapered outer shoulder 67 and a tapered inner shoulder 68 (not visible in FIG. 2). Substantially cylindrical central bore 66 extends along the entire length of grease injection tube 60.

FIG. 3 depicts a sectional view of prior art grease injection tube 60 taken along line 3-3 of FIG. 2. Central body section 61 has a rounded outer surface. Substantially cylindrical central bore 66 extends through central body section 61, and defines substantially smooth inner surface 61 a along the length of said bore 66.

FIG. 4 depicts a sectional view of prior art grease injection tube 60 taken along line 4-4 of FIG. 3. Upper end section 62 is disposed at the upper end of central body section 61 and has an outer diameter less than that of said central body section 61. Upper end section 62 has tapered outer shoulder 64 and tapered inner shoulder 65. Lower end section 63 is disposed at the lower end of central body section 61 and also has an outer diameter less than that of said central body section 61. Lower end section 63 also has tapered outer shoulder 67 and tapered inner shoulder 68. Substantially cylindrical central bore 66 extends along the entire length of grease injection tube 60.

Still referring to FIG. 4, during wireline operations, grease tube 60 is disposed within grease injection assembly 30 (such as depicted in FIG. 1). Wireline 51 is concentrically disposed through central bore 66 of grease tube 60. A beneficially-sized gap exists between the external surface of wireline 51 and internal surface 61 a of grease injection tube 60. In operation, grease or other viscous fluid having desired characteristics is introduced into such gap and maintained under pressure. Such grease or other viscous fluid fills the gap between the outer surface of wireline 51 and the inner surface 61 of grease tube 60, and forms a dynamic pressure seal. Referring back to FIG. 1, such pressure seal permits wireline tools 50 to be raised and/or lowered within well 10, while preventing pressurized fluids in well 10 from invading the annular space between wireline 50 and internal surface 61 a of grease tube 60, and escaping out of the top of lubricator 20.

In virtually all cases, wireline tools 50 have a larger outer diameter than the inner diameter of central bore 66 of grease injection tube 60. For this reason, tools 50 cannot pass through said central bore 66. Accordingly, prior to conducting wireline operations in a well equipped with conventional grease injection tube(s), the leading end of wireline 51 (without any wireline tools attached) must be threaded through central bore 66 of grease tube 60 (and any other grease tube used, in the event that multiple tubes are employed). Once the leading end of wireline 51 is threaded through the central bore 66 of such tubes 60, the desired wireline tools 50 are then connected to said leading end of wireline 51. In most cases, tools 50 are thereafter retracted into a lubricator, such as lubricator assembly 20 in FIG. 1, and said lubricator is in turn connected to the top of Christmas tree 12. Valve 12 a of said Christmas tree can then be opened, and wireline tools 50 can be conveyed into well 10.

FIG. 5 depicts a side perspective view of one embodiment of fully assembled grease injection tube 100 of the present invention. In the preferred embodiment, grease injection tube 100 comprises opposing elongate semi-cylindrical members 120 and 140 that can be joined together to form said grease injection tube 100. When assembled, grease injection tube 100 has a similar shape and substantially identical dimensions as prior art grease injection tubes (such as, for example, grease injection tube 60).

Elongate semi-cylindrical member 120 comprises substantially central body section 121. Upper end section 122 is disposed at the upper end of central body section 121 and has an outer diameter less than that of said central body section 121. Upper end section 122 also has tapered outer shoulder 124 and tapered inner shoulder 125. Lower end section 123 is disposed at the lower end of central body section 121 and also has an outer diameter less than that of said central body section 121. Lower end section 123 also has tapered outer shoulder 127 and tapered inner shoulder 128 (not visible in FIG. 5).

Elongate semi-cylindrical member 140 comprises substantially central body section 141. Upper end section 142 is disposed at the upper end of central body section 141 and has an outer diameter less than that of said central body section 141. Upper end section 142 also has tapered outer shoulder 144 and tapered inner shoulder 145. Lower end section 143 is disposed at the lower end of central body section 141 and also has an outer diameter less than that of said central body section 141. Lower end section 143 also has tapered outer shoulder 147 and tapered inner shoulder 148 (not visible in FIG. 5).

Elongate semi-cylindrical members 120 and 140 each have elongate semi-cylindrical central channels along their inner surfaces. When said semi-cylindrical members 120 and 140 are joined together, said channels combine to define a central bore extending along the length of grease injection tube 100. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 100.

FIG. 8A depicts an exploded perspective view of grease injection tube 100 of the present invention. As set forth above, grease injection tube 100 comprises opposing elongate semi-cylindrical members 120 and 140 that can mate together to form said grease injection tube 100.

Elongate semi-cylindrical member 120 comprises substantially central body section 121. Upper end section 122 is disposed at the upper end of central body section 121, and has tapered outer shoulder 124 and tapered inner shoulder 125. Lower end section 123 is disposed at the lower end of central body section 121 and also has tapered outer shoulder 127 and tapered inner shoulder 128 (not visible in FIG. 8A).

A plurality of bores 129 extends through elongate semi-cylindrical member 120. In the preferred embodiment, said bores 129 are oriented in pairs along the length of said elongate semi-cylindrical member 120. Further, said bores are oriented substantially perpendicular to the longitudinal axis of said elongate semi-cylindrical member 120.

Still referring to FIG. 8A, opposing elongate semi-cylindrical member 140 comprises substantially central body section 141. Upper end section 142 is disposed at the upper end of central body section 141, and has tapered outer shoulder 144 and tapered inner shoulder 145. Lower end section 143 is disposed at the lower end of central body section 141 and also has tapered outer shoulder 147 and tapered inner shoulder 148.

Central channel 150 extends along the inner surface of elongate semi-cylindrical member 140. In the preferred embodiment, said central channel 150 has a rounded inner surface and a substantially constant inner diameter along substantially the entire length of said channel 150. A plurality of threaded bores 149 extends through elongate semi-cylindrical member 140. In the preferred embodiment, said threaded bores 149 are aligned in pairs along the length of said elongate semi-cylindrical member 140, with one bore of each pair on one side of central channel 150, and the other bore of said pair on the other side of said channel 150. Further, said bores 149 are oriented substantially perpendicular to the longitudinal axis of said elongate semi-cylindrical member 140. When members 120 and 140 are combined, bores 149 are aligned with bores 129 of elongate semi-cylindrical member 120.

Still referring to FIG. 8A, elongate recesses 151 are provided along substantially the entire length, and on both sides, of central channel 150 of semi-cylindrical member 140. Further, a plurality of bosses 152 extend from the inner surface of said semi-cylindrical member 140, while a plurality of recesses 153 are disposed along said inner surface of same semi-cylindrical member 140. In the preferred embodiment, one boss 152 is paired with one recess 153, with such pairs of bosses/recesses spaced along the length of said semi-cylindrical member 140. Further, in the preferred embodiment, said pairs of bosses/recesses are disposed between pairs of threaded bores 149.

Gasket members 160 and 162 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 120 and 140. A plurality of bores 161 extends through said gasket members 160 and 162. In the preferred embodiment, the bores 161 of gasket member 160 are aligned with bores 161 of gasket member 162. Further, said bores 161 of gasket members 160 and 162 are aligned with pairs of threaded bores 149, bosses 153 and recesses 153. A plurality of set screws 170 are received in bores 129 of elongate semi-cylindrical member 120 and are threadably received within threaded bores 149 of elongate semi-cylindrical member 140.

FIG. 8B depicts a reverse exploded perspective view of the grease injection tube of the present invention depicted in FIG. 8A. Elongate semi-cylindrical member 120 comprises substantially central body section 121. Upper end section 122 is disposed at the upper end of central body section 121, and has tapered outer shoulder 124 and tapered inner shoulder 125. Lower end section 123 is disposed at the lower end of central body section 121 and also has tapered outer shoulder 127 and tapered inner shoulder 128.

A plurality of bores 129 extends through elongate semi-cylindrical member 120. In the preferred embodiment, said bores 129 are provided in pairs along the length of said elongate semi-cylindrical member 120. Further, said bores are oriented substantially perpendicular to the longitudinal axis of said elongate semi-cylindrical member 120.

Still referring to FIG. 8B, opposing elongate semi-cylindrical member 140 comprises substantially central body section 141. Upper end section 142 is disposed at the upper end of central body section 141, and has tapered outer shoulder 144 and tapered inner shoulder 145. Lower end section 143 is disposed at the lower end of central body section 141 and also has tapered outer shoulder 147 and tapered inner shoulder 148 (not visible in FIG. 8B).

Central channel 180 extends along the inner surface of elongate semi-cylindrical member 120. In the preferred embodiment, said central channel has a rounded inner surface and a substantially constant inner diameter along the length of said channel 180.

Still referring to FIG. 8B, a plurality of bosses 132 extend from the inner surface of said semi-cylindrical member 120, while a plurality of recesses 133 are disposed along said inner surface of same semi-cylindrical member 120. In the preferred embodiment, one boss 132 is paired with one recess 133, with such pairs of bosses/recesses spaced on both sides of central channel 180 along the length of said semi-cylindrical member 120. Further, in the preferred embodiment, said pairs of bosses/recesses are disposed between pairs of bores 129.

Gasket members 160 and 162 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 120 and 140. A plurality of bores 161 extends through said gasket members 160 and 162. Ridge 164 extends from the surface of gasket member 162 in the direction of elongate cylindrical member 140, while ridge 163 extends from the surface of gasket member 160, also in the direction of elongate cylindrical member 140. Ridges 163 and 164 are aligned with, and can be received within, elongate recesses 151 disposed on both sides of central channel 150 of semi-cylindrical member 140.

FIG. 6 depicts a sectional view of grease injection tube 100 of the present invention taken along line 6-6 of FIG. 5. When elongate semi-cylindrical members 120 and 140 are joined together, central channel 150 of elongate semi-cylindrical member 140 combines with central channel 180 of elongate semi-cylindrical member 120 to form a central bore extending along the length of grease injection tube 100. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 100.

Gasket members 160 and 162 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 120 and 140. In the preferred embodiment, gasket members 160 and 162 are constructed of rubber, elastomer or other sealing material. Ridge 164 extends from the surface of gasket member 162 in the direction of elongate cylindrical member 140, while ridge 163 extends from the surface of gasket member 160, also in the direction of elongate cylindrical member 140. Ridges 163 and 164 are aligned with and received within elongate recesses 151 disposed laterally along central channel 150 of semi-cylindrical member 140. Set screws 170 are received in bores 129 of elongate semi-cylindrical member 120 and are threadably received within threaded bores 149 of elongate semi-cylindrical member 140.

FIG. 7 depicts a sectional view of grease injection tube 100 of the present invention taken along line 7-7 of FIG. 5. When elongate semi-cylindrical members 120 and 140 are joined together, central channel 150 of elongate semi-cylindrical member 140 combines with central channel 180 of elongate semi-cylindrical member 120 to form a central bore extending along the length of grease injection tube 100. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 100.

Gasket members 160 and 162 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 120 and 140. Ridge 164 extends from the surface of gasket member 162 in the direction of elongate cylindrical member 140, while ridge 163 extends from the surface of gasket member 160, also in the direction of elongate cylindrical member 140. Ridges 163 and 164 are aligned with and received within elongate recesses 151 disposed on both sides of central channel 150 of semi-cylindrical member 140. Boss 152 of semi-cylindrical member 140 is received within recess 133 of semi-cylindrical member 120, while boss 132 of semi-cylindrical member 120 is received within recess 153 of semi-cylindrical member 140.

FIG. 9 depicts a side perspective view of alternative embodiment of fully assembled grease injection tube 200 of the present invention. In the preferred embodiment, grease injection tube 200 comprises opposing elongate semi-cylindrical members 220 and 240 that can be joined together to form said grease injection tube 200. When assembled, grease injection tube 200 has a similar shape and substantially identical dimensions as the grease injection tubes described above.

Elongate semi-cylindrical member 220 comprises substantially central body section 221. Upper end section 222 is disposed at the upper end of central body section 121 and has an outer diameter less than that of said central body section 221. Upper end section 222 also has tapered outer shoulder 224 and tapered inner shoulder 225. Lower end section 223 is disposed at the lower end of central body section 221 and also has an outer diameter less than that of said central body section 221. Lower end section 223 also has tapered outer shoulder 227 and tapered inner shoulder 228 (not visible in FIG. 9).

Elongate semi-cylindrical member 240 comprises substantially central body section 241. Upper end section 242 is disposed at the upper end of central body section 241 and has an outer diameter less than that of said central body section 241. Upper end section 242 also has tapered outer shoulder 244 and tapered inner shoulder 245. Lower end section 243 is disposed at the lower end of central body section 241 and also has an outer diameter less than that of said central body section 241. Lower end section 243 also has tapered outer shoulder 247 and tapered inner shoulder 248 (not visible in FIG. 9).

Elongate semi-cylindrical members 220 and 240 both have elongate central channels along their inner surfaces. When said semi-cylindrical members 220 and 240 are joined together, said channels combine to form a central bore extending along the length of grease injection tube 200. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 200.

FIG. 11A depicts an exploded perspective view of a portion of the alternative embodiment of the grease injection tube 200 depicted in FIG. 9. Central channel 250 extends along the inner surface of elongate semi-cylindrical member 240. In the preferred embodiment, said central channel 250 has a rounded inner surface and a substantially constant inner diameter along the length of said channel 250. Elongate recesses 251 are provided along substantially the entire length, and on both sides, of central channel 250 of semi-cylindrical member 240. Further, elongate slot 253 is provided on one side of central channel 250 and extends along substantially the entire length of semi-cylindrical member 240, while key-like extension 252 is provided on the opposite side of central channel 250 and extends along substantially the entire length of semi-cylindrical member 240. Substantially cylindrical sealing elements 260, which are formed of rubber, elastomer or other suitable sealing material, are sized to fit within elongate recesses 251.

FIG. 11B depicts an exploded perspective view of the alternative embodiment of the grease injection tube 200 depicted in FIG. 9. Central channel 280 extends along the inner surface of elongate semi-cylindrical member 220. In the preferred embodiment, said central channel 280 has a rounded inner surface and a substantially constant inner diameter along the length of said channel 280. Elongate recesses, similar to elongate recesses 251 of semi-cylindrical member 240, are provided along substantially the entire length, and on both sides, of central channel 280 of semi-cylindrical member 220. Further, elongate slot 233 is provided on one side of central channel 280 and extends along substantially the entire length of semi-cylindrical member 220, while key-like extension 232 is provided on the opposite side of central channel 280 and extends along substantially the entire length of semi-cylindrical member 220. Substantially cylindrical sealing elements 260 are constructed of rubber, elastomer or other suitable sealing material.

FIG. 10 depicts a sectional view of grease injection tube 200 taken along line 10-10 of FIG. 9. When elongate semi-cylindrical members 220 and 240 are joined together, central channel 250 of elongate semi-cylindrical member 240 combines with central channel 280 of elongate semi-cylindrical member 220 to form a central bore extending along the length of grease injection tube 200. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 200.

Sealing members 260 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 220 and 240. Key-like extension 252 of semi-cylindrical member 240 is slidably received within elongate slot 233 of semi-cylindrical member 220, while key-like extension 232 of semi-cylindrical member 220 is slidably received within elongate slot 253 of semi-cylindrical member 240. Referring back to FIG. 11B, it is to be observed that semi-cylindrical members 220 and 240 are joined together by sliding said components longitudinally in order to mate said members.

FIG. 12 depicts a side perspective view of yet another alternative embodiment of fully assembled grease injection tube 300 of the present invention. In the preferred embodiment, grease injection tube 300 comprises opposing elongate semi-cylindrical members 320 and 340 that can mate together to form said grease injection tube 300.

Elongate semi-cylindrical member 320 comprises substantially central body section 321. Upper end section 322 is disposed at the upper end of central body section 321 and has an outer diameter less than that of said central body section 321. Upper end section 322 also has tapered outer shoulder 324 and tapered inner shoulder 325. Lower end section 323 is disposed at the lower end of central body section 321 and also has an outer diameter less than that of said central body section 321. Lower end section 323 also has tapered outer shoulder 327 and tapered inner shoulder 328 (not visible in FIG. 12).

Elongate semi-cylindrical member 340 comprises substantially central body section 341. Upper end section 342 is disposed at the upper end of central body section 341 and has an outer diameter less than that of said central body section 341. Upper end section 342 also has tapered outer shoulder 344 and tapered inner shoulder 345. Lower end section 343 is disposed at the lower end of central body section 341 and also has an outer diameter less than that of said central body section 341. Lower end section 343 also has tapered, outer shoulder 347 and tapered inner shoulder 348 (not visible in FIG. 12).

FIG. 13 depicts a sectional view of grease injection tube 300 taken along line 13-13 of FIG. 12. When elongate semi-cylindrical members 320 and 340 are joined together, central channel 350 of elongate semi-cylindrical member 340 combines with central channel 380 of elongate semi-cylindrical member 320 to form a central bore extending along the length of grease injection tube 300. In the preferred embodiment, said central bore has a substantially circular cross-section and substantially constant diameter along the entire length of said grease injection tube 300.

Much like grease injection tube 200 depicted in FIGS. 9, 10, 11A and 11B, sealing members 360 are disposed between the inner surfaces of opposing elongate semi-cylindrical members 320 and 340. In the preferred embodiment, sealing members 360 are constructed of rubber, elastomer or other similar sealing material. Key-like extension 352 of semi-cylindrical member 340 is received within elongate slot 333 of semi-cylindrical member 320, while key-like extension 332 of semi-cylindrical member 320 is received within elongate slot 353 of semi-cylindrical member 340. Much like grease injection tube 200, semi-cylindrical members 320 and 340 are joined by longitudinally sliding said components together.

Referring back to FIG. 12, semi-cylindrical Member 320 has side flange members 380, while semi-cylindrical member 340 has side flange members 390. A plurality of apertures is disposed in spaced relation along the length of said flange members 380 and 390. Referring to FIG. 13, in the preferred embodiment, flange members 380 and 390 are disposed against one another when semi-cylindrical members 320 and 340 are joined together. In this configuration, the apertures of flange members 380 are aligned with the apertures of flange members 390. Fasteners, such as threaded screws 400, are received within said aligned apertures of flange members 380 and 390, and secured in place using threaded nuts 401. By tightening threaded nuts 401 on threaded screws 400, flange members 380 and 390 and, thus, semi-cylindrical members 320 and 340, are drawn together. By compressing semi-cylindrical members 320 and 340 together, sealing members 360 are likewise compressed and energized, thereby resulting in greater pressure sealing capacity between said semi-cylindrical members 320 and 340.

Yet another alternative embodiment of the grease injection tube of the present invention comprises two opposing semi-cylindrical members attached to one another using a hinge mechanism, as well as at least one fastening means to keep said opposing semi-cylindrical members joined together in the closed position (generally around wireline). In the preferred embodiment, said hinge mechanism is disposed along one lateral side of said opposing semi-cylindrical members. Said fastening means can comprise at least one threaded bolt. Alternatively, said fastening means can comprise a releasable latch mechanism.

The grease injection tubes of the present invention and alternative embodiments, including alternative embodiments 100, 200 and 300, permit replacement of said tubes while wireline is suspended in a well, and without requiring such wireline or wireline tools to be completely removed from a well. Further, such grease injection tubes of the present invention permit removal/replacement of such tubes without the need for severing tools from wireline.

As discussed in detail above, the process of replacing conventional prior art grease injection tubes can be an involved and time-consuming process, especially where drilling rigs are involved. Because drilling rigs and associated goods and services are typically rented on a daily or hourly basis, the time delay associated with replacing conventional grease tubes can be extremely expensive. Further, as discussed above, the current method of replacing grease tubes requires the cutting of wireline and splicing of tools on such cut wireline, which can result in reduced or diminished performance by such wireline and associated tools.

When replacement of the wireline tubes of the present invention becomes necessary or desirable—including during times that wireline and any associated wireline tools are in a well—the wireline blowout preventers can be closed around the wireline at the surface. In this manner, the wireline (and any associated tools) remain in the well, with any well pressure safely isolated below such blowout preventers. Thereafter, any trapped pressure can be released from the lubricator and grease injection assembly, and the grease injection assembly can be opened to expose the grease tubes of the present invention. Once exposed, the grease injection tubes of the present invention can then be removed and replaced with new tubes; such removal and replacement can be performed without retrieving the wireline and/or wireline tools from the well, cutting the wireline tools from the wireline, or splicing such tools back on the wireline. Thereafter, the grease injection assembly can be reinstalled, the grease injection assembly and lubricator can be re-sealed (if necessary), and the wireline blow out preventers can be re-opened. Ongoing wireline operations can then be safely resumed.

The above-described invention has a number of particular features that should preferably be employed in combination, although each is useful separately without departure from the scope of the invention. While the preferred embodiment of the present invention is shown and described herein, it will be understood that the invention may be embodied otherwise than herein specifically illustrated or described, and that certain changes in form and arrangement of parts and the specific manner of practicing the invention may be made within the underlying idea or principles of the invention. 

1. A wireline grease injection apparatus comprising: a) a housing having an internal chamber, an inlet and an outlet; b) at least one grease tube disposed within the chamber of said housing comprising: i) a first semi-cylindrical member having a top, a bottom, a longitudinal channel extending from said top to said bottom, and a plurality of apertures extending through said first semi-cylindrical member and oriented substantially perpendicular to said channel; and ii) a second semi-cylindrical member having a top, a bottom, a longitudinal channel extending from said top to said bottom, and a plurality of apertures extending through said second semi-cylindrical member and oriented substantially perpendicular to said channel, wherein said channels of said first and second semi-cylindrical members are aligned to form an elongate bore extending through said grease tube, and said apertures of said second semi-cylindrical member are aligned with the apertures of said first semi-cylindrical member; and iii) a plurality of fasteners disposed through said aligned apertures of said first and second semi-cylindrical members.
 2. The wireline grease injection apparatus of the claim 1, wherein said elongate bore is substantially cylindrical.
 3. The wireline grease injection apparatus of claim 1, wherein said apertures of said first or second semi-cylindrical members are threaded.
 4. The wireline grease injection apparatus of claim 3, wherein said fasteners comprise threaded bolts.
 5. The wireline grease injection apparatus of claim 1, further comprising at least one pressure seal between said first and second semi-cylindrical members.
 6. The wireline grease injection apparatus of claim 5, wherein said at least one pressure seal further comprises at least one sealing member disposed along each side of said elongate bore.
 7. The wireline grease injection apparatus of claim 6, wherein said sealing members comprise at least one elastomer.
 8. A wireline grease injection apparatus comprising: a) a housing having a chamber, an inlet and an outlet; b) at least one grease tube disposed within the chamber of said housing comprising: i) a first semi-cylindrical member having a top, a bottom, a longitudinal channel extending from said top to said bottom, and at least one extension disposed on one side of said channel and a slot disposed on the opposite side of said channel; and ii) a second semi-cylindrical member having a top, a bottom, a longitudinal channel extending from said top to said bottom, at least one extension disposed on one side of said channel and a slot disposed on the opposite side of said channel, wherein said at least one extension of said first semi-cylindrical member is slidably received within the slot of said second semi-cylindrical member, said at least one extension of said second semi-cylindrical member is slidably received within the slot of said first semi-cylindrical member, and said channels of said first and second semi-cylindrical members are aligned to form an elongate bore extending through said grease tube.
 9. The wireline grease injection apparatus of claim 10, further comprising at least one pressure seal between said first and second semi-cylindrical members.
 10. The wireline grease injection apparatus of claim 9, wherein said at least one pressure seal further comprises at least one sealing member disposed along each side of said elongate bore.
 11. The wireline grease injection apparatus of claim 10, wherein said sealing members comprise at least one elastomer.
 12. A wireline grease injection apparatus comprising: a) a housing having an internal chamber, an inlet and an outlet; b) at least one grease tube disposed within the chamber of said housing comprising: i) a first semi-cylindrical member having a top, a bottom, a first side, a second side, a longitudinal channel extending from said top to said bottom, and flanges extending from said first and second sides, wherein a plurality of apertures extend through said flanges and are oriented substantially perpendicular to said channel; and ii) a second semi-cylindrical member having a top, a bottom, a first side, a second side, a longitudinal channel extending from said top to said bottom, and flanges extending from said first and second sides, wherein a plurality of apertures extend through said flanges and are oriented substantially perpendicular to said channel, wherein said channels of said first and second semi-cylindrical members are aligned to form an elongate bore extending through said grease tube, and said apertures in the flanges of said second semi-cylindrical member are aligned with the apertures in the flanges of said first semi-cylindrical member; and iii) a plurality of fasteners disposed through said aligned apertures in the flanges of said first and second semi-cylindrical members.
 13. The wireline grease injection apparatus of the claim 12, wherein said elongate bore is substantially cylindrical.
 14. The wireline grease injection apparatus of claim 12, wherein said fasteners comprise threaded bolts.
 15. The wireline grease injection apparatus of claim 12, further comprising at least one pressure seal between said first and second semi-cylindrical members.
 16. The wireline grease injection apparatus of claim 15, wherein said at least one pressure seal further comprises at least one sealing member disposed along each side of said elongate bore.
 17. The wireline grease injection apparatus of claim 16, wherein said sealing members comprise at least one elastomer. 